In some Multiple-Input Multiple-Output (MIMO) communication systems. multiple cells use Cooperative Multipoint (CoMP) transmission schemes for coordinating downlink MIMO transmissions to User Equipment (UEs). Third Generation Partnership Project (3GPP) Long Term Evolution-Advanced (LTE-A) systems, for example, use or contemplate the use of multiple CoMP modes such as Dynamic Point Selection (DPS), Dynamic Point Blanking (DPB), Cooperative beamforming (CB) and Joint Transmission (JT).
The CoMP modes used in LTE-A are specified, for example, in “3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Coordinated multi-point operation for LTE physical layer aspects (Release 11),” 3GPP TR 36.819, version 11.0.0, September, 2011, which is incorporated herein by reference. When using CoMP, the cooperating cells typically configure their transmissions based on channel feedback provided by the UEs.
Feedback in communication systems is sometimes calculated based on interference measurements performed by the UEs. Various interference measurements techniques are known in the art. For example, U.S. Patent Application Publication 2009/0268630, whose disclosure is incorporated herein by reference, describes a user device on a wireless network that includes a receiver, a noise detector and a noise determiner. The receiver receives downlink data communications from a base station that indicates an allocation of time/frequency resource blocks at least to user devices that are communicating with the base station. The noise detector measures noise in a time/frequency resource block, comprising plural time/frequency bins, that is not allocated to one of the user devices (e.g., allocated to a virtual user device). The noise determiner determines a level of interfering noise based on noise in the resource block that is not allocated to one of the user devices.
The description above is presented as a general overview of related art in this field and should not be construed as an admission that any of the information it contains constitutes prior art against the present patent application.